Jet protector for a water wheel



March 1, 1960 w. F. BOYLE 2,926,887

JET PROTECTOR FOR A WATER WHEEL Filed Nov. 5, 1957 INVENTOR. WILL/AM F BOYLE 46 W g WM A TTO/PNEVS United States Patent JET PROTECTOR FOR A WATER WHEEL William F. Boyle, San Anselmo, Calif., assignor to Baldwin-Lima-Hamilton Corporation, a corporation of Pennsylvania Application November 5, 1957, Serial No. 694,600

3 Claims. (Cl. 253-136) My invention is especially useful in an environment in which water wheels of the Pelton type are involved. In this environment there is provided a rotating water wheel having a series of buckets on its periphery. These are struck by a water jet issuing from a nozzle arranged substantially tangent to the rotating buckets. The nozzle is usually designed to project within the casing enclosing the water wheel. The nozzle is carefully contoured and arranged so that the issuing jet has a carefully established and maintained envelope. Any interference with the designed envelope of the jet is productive of inefficiency in the utilization of the propulsion water.

In many installations there are several nozzles provided within the same casing each arranged to be tangent to the water wheel. In the operation of a device of this sort, the spent water emerging from the buckets after imparting most of its energy thereto is discharged as quickly and directly as possible from the casing in order not to interfere with the rotating parts or with the jets. However, some nearly spent water before discharge travels toward and strikes the jets. Some water is adherent to the buckets and other rotating members and tends to fly off within the casing with enough energy to cause detrimental effects. This is particularly true in a multi-jet installation wherein the space or volume for dissipation of the spent water between jetsis restricted.

While the operation of a water wheel is normally on as clean water as can be provided, in many hydraulic installations the water, although devoid of major debris, nevertheless contains some abrasives and miscellaneous, small debris. This is sometimes immediately harmful in itself or over a period of time can produce a certain, unwanted erosion and a major wear of some of the parts. Material flying around within the water Wheel housing, whether simply spent water on its way to discharge or debris of various sorts impinges upon the issuing jet or jets. This is sometimes in sufficient amount to distort or destroy partially the desired jet envelope and to result in substantial ineiiiciency.

Various nozzle contours and protectors have been afforded to fend off unwanted materials before they can strike the issuing jet. These devices have been partially satisfactory, but have introduced further difficulties in that sometimes debris of a fair size gets lodged within or between the guard or protector and the whirling water wheel buckets. Such jams cause breakage, either of some of the buckets or of the guards or both and give rise to additional metal particles flying around within the water wheel casing causing serious damage and shut down. Vibration incident to the operation of the wheel and the nozzles is imparted to the guards heretofore used and eventually metal fatigue has caused partial dislodgment and breakage of the guards. There is sometimes sufficient impingement of hydraulic particles upon the guard to cause cavitation and sloughing off of some of the metal thereof. Thus, while the guards heretofore provided have directly protected the envelope of the jets and have permitted maintenance of the desired efficiency, they themselves have introduced other diificulties which have been extremely serious.

It is therefore an object of the invention to provide a jet guard or protector for a water wheel which will protect a jet without introducing other deleterious factors.

An additional object of the invention is to provide a jet protector for a water wheel which will protect the jet against the most frequent impinging particles, yet will not fail if a major object momentarily intrudes.

Another object of the invention is to provide a protector of a yielding nature which itself will pass a major impingement without causing deleterious effect upon the water wheel or the nozzle.

A still further object of the invention is in general to provide an improved jet protector.

A still further object of the invention is to provide a jet protector which readily can be utilized in water wheels of present design with only very minor changes or perhaps no changes therein at all.

Other objects of the invention, together with the foregoing, are attained in the embodiment of the invention described in the accompanying description and illustrated in the accompanying drawings in which:

Figure 1 is a side elevation of a portion of a Water wheel and its accompanying nozzle with the jet protector of the invention installed, the jet protector being shown in cross section on a diametrical plane through the nozzle axis.

Figure 2 is an end elevation of the nozzle and jet protector shown in Figure 1, the plane of the view being indicated by the line 2-2 of Figure 1.

Figure 3 is an isometric view of a jet protector by itself.

Figure 4 is a cross section the plane of which is indicated by the line 4-4 of Figure 2 and drawn to an enlarged scale.

While the jet protector according to the invention can be utilized in a number of different environments and can be readily adapted to the specific environment in which it is specially used it has successfully been operated in connection with relatively large size hydraulically driven wheels of the Pelton type propelled by water jets issuing from multiple nozzles.

As a typical showing of such an environment, there is in Figure 1 disclosed a water wheel 6 having a plurality of diagrammatically illustrated buckets 7 disposed on its periphery. The buckets revolve in the direction of the arrow 8 in the figure and are arranged so that the various bucket tips 9 rotate in a peripheral circle 11 having the maximum radius or maximum diameter of the water wheel 6. The water wheel 6 has the customary mounting shaft (not shown) rotating on its axis centrally of the circular path 11 and is encompassed by the customary enclosing housing (not shown).

Suitably disposed within the housing and substantially tangentially to the water wheel 6 is a nozzle 13. This is representative of a plurality of such nozzles arranged in similar, substantially tangential, equally spaced locations around the periphery of the water wheel 6. It is customary to employ, for example, four such nozzles although there is no necessary limiting number. The nozzle 13 normally ends in a terminal ring 14 surrounding a circular discharge aperture 16. It has an axis 17 extending chordally of the peripheral circle 7 and substantially tangent to the pitch line of the buckets 7. The ring 16 defines the outer envelope 18 of a water jet 19 issuing from the nozzle 19 and impinging upon the buckets 7 as they proceed in the direction of the arrow 8 and successively come into the path of the jet 19. To control the jet there is usually provided a nozzle needle 21 moving into and out of the ring 14 in the direction of the axis 17 so that the jet 19 is sometimes small and sometimes large. The ring 14 is secured to the nozzle 13 by a plurality of removable fastenings such as nuts 22 engaging studs 23 projecting from the nozzle body so that the ring 14 is readily removable and can be replaced when worn or when a. different size is requisite.

Pursuant to this invention there is preferably provided a guard or shield or protector for the jet 1. so that flying water particles or even debris will not materially interfere with the envelope 18 of the jet. There is disposed between the adjacent portion of the nozzle 13 and the peripheral circle 11; of the bucket 7 a protector 2h. This is not a rigid member but preferably is a flexible body of elastonieric material. The protector 26 has suflicient stiffness or hardness to maintain its normal shape against the impingement of the usually encountered flying water particles but has suflicient flexibility and yieldability so as to be deflected by large bodies such as flying debris.

The protector 26 preferably includes an arcuate base portion 27 of planar extent preferably confined between parallel, planar surfaces 28 and 29. The elastomeric material of the arcuate base portion 27 is conveniently formed with apertures 31 receiving molded-in sleeves 32. The sleeves are externally corrugated and have central bores 33 of sufficient size to slide easily over the studs 23 when the nuts 22 are removed therefrom.

The arcuate extent of the planar portion 27 of the protector is in the present instance suiiicient for the protector to be held in position by six of the studs 23 and their accompanying nuts 22. Since the metallic inserts 32 limit the amount that the nuts 22 can be tightened, the material of the planar portion is left flexible and yielding so that in the event there is any misalignment or distortion it can readily be taken up. Preferably, a keeper or strap 41 of an arcuate configuration conforming substantially to that of the arcuate planar portion of the protector also is disposed over the studs 23 and is immediately contacted by the nuts 22 or intervening lock washers 42, thus affording a shield and a secure attachment for the protector.

integrally molded with the planar portion 27 and formed of the same or similar yielding, elastomeric material is an apron 43 projecting outwardly from the base 27. The apron 43 is of substantially the same dimension as the radial distance between the nearest parts of the nozzle 13 and the peripheral circle it so as to come very close to the tips 9 of the buckets '7. There is a slight clearance remaining. The apron 43 is of a curved configuration and extends from the parallel plane of the surface 29 to a termination in another parallel plane defining a surface 44. The inner curved surface 46 of the apron is parallel to the outer curved surface 47 thereof. The circumferential extent of the apron is substantially the same as that of the arcuate base 27 so that the apron terminates between one end surface 48 and another end surface 49, these latter surfaces being parallel to each other. The arcuate extent of the apron is sufificient to overlie the jet 19 and to extend on either side thereof. That is, as shown especially in Figure 2, the arcuate extent or peripheral extent of the apron 43 is suflicient to overlie the diameter of the jet with something to spare on either side.

With this arrangement the protector can readily be bolted in position on an existing nozzle provided only that long studs 23 are first positioned therein. If new studs must be provided, only enough need be provided to match the number of fastening apertures or reinforcements 32.

The member 41 is put into position and the series of nuts 22 is tightened.

if, during the operation of the wheel, one of the buckets should be slightly out of line or if there should be some slight error in dimension or in installation position, or

even if the tips 9 of the buckets strike the protector 26 no damage is done.

As water discharges from the buckets it merely strikes the upstream side 47 of the deflector and is kept away from any impingement upon the jet 19 which therefore is maintained in its desired condition. This is true not only of particles travelling exactly in the direction of the arrow 3, but also for other particles which come at various angles toward the jet, the peripheral extent of the deflector being sufficient to keep substantially all of such particles away. If minor debris such as sand and the like strikes the deflector, it is deflectedto one side or the.

other without having any encounter with the jet 19. If a large piece of debris travels toward the deflector, the apron itself may be momentarily deflected and move out of position. The jet may be momentarily disrupted but the large debris does not cause any breakage and does not jam.

incidental vibration due to the operation of the wheel does not produce any ultimate fatigue in the material of the effector, the life of which is indefinite. Particles of the deflector torn off or detached are themselves harmless to the surrounding mechanism and are ultimately discharged without causing any damage. Additionally, impact against the deflector does not produce cavitation so no material of consequence is detached from the deflector. Should there ultimately be excessive deterioration of the deflector, it can readily be removed and replaced by another like body.

There has been provided, in accordance with this invention, a jet protector for a water wheel that is a considerable improvement over those heretofore used, that is effective to deflect the normally encountered water par- ,ticles and items of small abrasive debris but that can yield under excessive impact without causing any damage and that if disintegrated or partially detached does not itself cause any damage.

What is claimed is:

1. A jet protector for a water wheel comprising a water wheel having buckets movable within a peripheral circle, a nozzle located to discharge a jet onto said buckets, a flexible apron extending partly around said jet and projecting toward said circle, and means securing said apron to said nozzle.

2. A jet protector comprising a water wheel, a nozzle designed to issue a jet against said water wheel, an arcuate apron of flexible elastomeric material concentric with said jet and extending in the general direction of issue of said jet, and means removably securing said apron to said nozzle.

3. A jet protector comprising a water Wheel, a nozzle disposed approximately tangentially of said wheel, fasteners on said nozzle, an arcuate base portion having apertures therein to accommodate said fasteners, and an apron of flexible elastomeric material and of curved configuration extending from said base portion toward said wheel.

References Cited in the file of this patent UNITED STATES PATENTS 1,713,405 Stansfield May 14, 1929 1,807,044 Merrilics May 26, 1931 2,038,234 Olen Apr. 21, 1936 2,156,921 Moody May 2, 1939 FOREIGN PATENTS 28,411 Norway Nov. 12, 1917 426,016 Great Britain Mar. 26, 1935 

